Composition comprising a vinylidene monomer and an unsaturated polyester containing an adduct of hexahalocyclopentadiene and article incorporated therewith



GOMBOSHION: comnrsme- A V-INYLIDENE MONOMERF AN uNsAruRArE-n: BQLY- nsrnn CONTAINING; Annual or a HALOCYCLOPENIADIENEH AND urrcrnv IN; 'CORFORATED THEREWITH Paul; Ruhitschek, Wilson; and Claude Thomas Bean; Niagara; Fang. N32,. assignors; to Hooker Chemical l'orporation', Niagara. Falls, NE aicorporzition of New York No' lfirawin'g. origi alapplication January 24, 1957;

S rra-1 m. 635;95 1. Divided and' tliis-application sp tembeni;L958,-Serial No:764,473

10; Claims. v (G11 154-43) This invention relates to new resinous compositions, and to methods for their manufacture; comprisihgafco: polymerizahle mixture ofi' an unsaturated polyester (also referred to in the art as anunsaturated alkyd; or, unsaturated" linear polyester of'unsaturated' polyester 'chain resin), andanunsaturatedcross-linking agent, said'imixture including a. chemically combined component? which imparts ila'me. retardance to the polymerized'mixture and which is of an adduct of'a 1-4 addition.ofihexahalocyclopentadiene with a dienophile ashereinafter defined; This invention also relates tothe polymerized flame retardant compositions in their, finally reacted form, that is, as resinous, insoluble, infusible',.copolymers, and'. to methods for their preparation.

This is a division of the parentlapplicationSeriaPNo. 635,951, filed January 24,, 19571 The production of infusihle, insoluble polyester resins which are flame retardant and have high resistance "of heat is of considerable commercial" importance. For instance, castings, moldings, foamed articles or laminated structures bonded: by polyester type resins are for many uses required; or at least desired, to be resistant to tire and'are also required to endure heat without deterioration.

2. ester resins, and the; property ofwbeingg, able re produce satisfactory articles of: commerce. may; be seriously paired Other, attempts to.:-impart. flame retardancetar'e also known. which involve chemically; combining; tetra: chlorophthalic acid. on anhydride in: the polyester" resin.- Compositions so produced are chemically unrelated to the products of this invention; they have only poor flame retardant properties and they usually possess low stability and low strength atielevated temperatures; theretbre, they are not entirely satisfactory for manyapplications. Still other attempts involving the use off certairn unsaturated A typical illustration of antapplication having such a requirement is had in castings for liveelectrical. contacts which. must not be ignited by sparks or be deteriorated by heat generated therein. Structural members, pipes, wall coverings and panels and miscellaneous items such as. ashtrays, etc., are further illustrations where flame retardance is desirable,

Heretofore certain chemical adducts have been disclosed as being useful in the preparation ofpol'yester resins; for example, it isknown that the maleic acid-cyclopentadiene Diels-Alder adduct resulting from the diene synthesis and its reaction products with alpha, beta-unsaturated dicarboxylic acids or anhydrides and glycols form resinous compositions which may be made insoluble and infusible by further reaction with copolymerizable olefinsto form a cross-linked copolymen Such compositions-are chemically different from the products of this invention because the double bond remaining in the linear-unsaturated polyester so produced'is highly reactive and can enter directly into the cross-linking reaction, whereas, the corresponding linkage the halogen-c011 taining derivatives employedlin making'the compositions of this invention 'is non-reactive. ii1. saidfcopolymerizationfreactioni moreover, they do not'possess flame re-. tardance; Attempts have been made to impart flame retardance to such hydrocarbon type resinous polyester.

compositions by incorp oratingtherein inert fireproofing agents, such as antimony oxideior'chlorinat'ed paraffin wax, asfillrs, which do not enter, into chemical reaction withtlie-components-of e res nih' w ye hi esult i i a l'ossin the desirable properties, particularly withrespect to heat resistance, which are usually associated with polyorganic phosphorus. compounds as" cross-li'nkiiig agents which impart flame retardance to the final polyester resin have likewise been found unsatisfactory.

It is an object ofthisinvention to provide resinous compositionswhich are highly resistant to burning and yet possess many of the desirable characteristics-usua11y associated with polyester resins. A,f urt-her object is to provide resinous compositions which are highlyr esistant to exposure:at:elevatedtemperaturesi; 'A still further object is to prepare resinous compositions which are suitable for casting, molding, foaming or laminating and which are characterized by possessing the desirable prop: erti'es'usually reqnired'in" resins in thepreparation'ofcast ings,mo1dings; foamed'articles. and laminates, and which are also characterized by being capable of forming; ar tricl'es'of commerce which have a pleasing appearance wide utility; A particular object ofthisinvention is to prepare resinous compositions which are characterizedby high impact resistance and improved. toughness. and? fiexa ibility. Another object of'thisinvention is tomake'ava'il able in commerce compositions comprising a mixture of an unsaturated polyester and an olefinic: cross-linking agent, Withor Without the presence ofi catalysts; and/or inhibitors andlor' chain terminating agents and/ or promotersor" accelerators; which are capable oficoplymeri'zation t'o'an insoluble, infusibl'e, fire resistant polyester resin. A further objective is to provide methods for chemically combining hexahalocyclopentadienes in the form, of, anadduct into the polyesters; A still fiirther objective. is to providemethods for the preparation of these unsatu rated polyesters and, their combination with olfefiuiee rdsse linking agents. These objects, andf'still others which, become apparent to those skilledin the art'on. considerintion of our specification and claims, are accomplished. at

. the present invention.

In accordance with this invention the unsaturated po ester, may contain the component which impartsflame. tard'ance in either thepolycarboxylic acid or anhyd'ride unit of'the' polyester. The'unsaturatedi polyester mus];

. contain unsaturation which is capable of eopo1y eriz'atidn linking reaction' We.render'such'polyesterscopoly -reaction adducts of hexahalocyclopentadienes wirhmone olefinic polycarboxyli'c, acids or anhydrides, or'rriono-ole} finic. polyhyd'ric alcohols 01. esters. thereof including acid chloridesis not sufiiciently reactive to enter into the cross;

able in v the crossrlinkingj reaction. by incorporattn I- m este rification product a. reactive. andluiisaturated. ingredient. which retains. its active unsat u'ati'on. aftenbeing chemically combined in the, polyesterehain. Alternatiyerg ly',.or in addition to, including flame retardant components,- in' the unsaturated; polyester, as justdescribed; and in aeL-r cordance with thisi'mtention, the cross-linking agentrmase c ontaiiith'ecomponent which: imparts: flame retardancea re the polyester resins of this invention. I I

The reactant components which impart flameretardance to the final polymerized resinous compositions by their incorporation in either the linear polyester or the unsaturated cross-linking agent may best be prepared by effecting the chemical addition of a hexahalocyclopentadiene with an unsaturated polycarboxylic acid or acid anhydride or acid halide, or an unsaturated polyhydric alcohol, or esters thereof, presumably in accordance with the following equations, in which the specific reactants are given for purposes of illustration only:

These, and similar Diels-Alder type reaction adducts of hexahalocyclopentadienes which are more fully disclosed hereinafter, can be esterified with a polyhydric alcohol or a polycarboxylic acid, to produce a soluble polyester chain containing the olefinic linkage originally present in the Diels-Alder adduct, as exemplified by the following product formed by esterification of the product of the Reaction I with ethylene glycol:

The olefinic linkage contained in such chlorine containing polyester chains (III), has been found by us to be unreactive in the coplymerization reaction with olefinic cross-linking agents, such as styrene, vinyl acetate, divinyl compounds, diallyl compounds, etc., even in the presence of the most active catalysts for such reactions. However, to render polyesters containing the Diels-Alder adducts of hexahalocyclopentadiene copolymerizable with olefinic cross-linking agents, whereby infusible, insoluble and flame retardant copolymers may be produced, we introduce copolymerizable unsaturation into the polyester chain by esterifying the foregoing components in the presence of a reactive unsaturated chemical ingredient which is capable of'rendering the polyester copolymerizable even after it is in chemical combination in the polyester molecule. The preparation of said adduct used in said polymerizable mixture is such that a polymerized cross-linked resin having preferably a chlorine content between preferably to 45 percent by weight is obtained. A particularly suitable material for this use is maleic anhydride; however any unsaturated polycarboxylic acid or anhydride, or, polyhydric alcohol, or, esters thereof, including the acid chlorides, capable of esterification without losing its ability to copolymerize with olefinic cross-linking agents may be employed. Alternatively, or in addition to providing unsaturation in this manner, we may also provide for it by employing a Diels-Alder reactant with hexahalocyclopentadiene which has more than mono-olefinic unsaturation, for example, a di-olefin or an acetylenic compound, and which retains, after being esterified in the polyester chain an unsaturated linkage reactive in the cross-linking reaction.

i The resinous copolymers of this invention may be prepolymerizing the mixture to form an insoluble, infusible polyester resin. Another method which may be employed for producing resinous copolymers of this invention which is in accordance with our findings comprises effecting the chemical addition of hexahalocyclopentadiene to less than I the total theoretical number of olefinic linkages contained in an unsaturated polyester molecule. For example, by effecting the Diels-Alder reaction of one molecule of hexahalocyclopentadiene with more than one molecule of ethylene glycol maleate, a product is produced which contains the hexahalocyclopentadiene in chemical combination in the polyester chain and which also contains active unsaturation which is copolymerizable in the crosslinking reaction; the product so produced is then mixed with the chosen olefinic cross-linking agent and thereafter copolymerized in a manner similar to that described.

Esterification of the desired ingredient may be effected in the presence of esterification catalysts and/or chain terminating agents. A preferred procedure involves introducing the selected ingredient to be esterified, in predetermined proportions, into a suitable esterification vessel provided with heating and/ or cooling means, an agitator, means for maintaining an atmosphere of an inert gas such as nitrogen or carbon dioxide over the reaction mixture, means for removing water of esterification, an

inlet, an outlet, and any other accessories necessary for the reaction. The charge reactants are blanketed with an inert atmosphere, then agitated and heated to effect the reaction for the specified period of time. After the desired degree of reaction has been attained, as conveniently determined by employing the acid number tech- I nique or measuring the amount of water liberated, the reaction mixture is cooled. The resulting product, if solid, and if prepared in accordance with the first procedure described, is broken up and then mixed with the olefinic cross-linking agent at room temperatures, preferably in the presence of a polymerization inhibitor. If prepared in accordance with the second method, a hexahalocyclopentadiene is chemically added to a soluble unsaturated polyester molecule in an amount insufficient to react out all the double bonds in the polyester and the material resulting by this treatment is then compounded with the olefinic cross-linking agent.

We have found that the cross-linking agent may be advantageously combined with unsaturated polyesters prepared in accordance with these methods while the unsaturated polyester is at an elevated temperature and that the olefinic cross-linking agent may also be at an elevated temperature thereby facilitating solution and mixing.

, To prevent premature polymerization at this stage, a polymerization inhibitor is advantageously added to the mixture, or, preferably to one of its components prior to mixing, especially if the mixture is to be stored or shipped in commerce prior to curing or effecting the copolymerization reaction 7 into the insoluble, infusible, polyester resin. Alternatively, or in addition to including a polymerization inhibitor, a catlyst and/or promoter for the copolymerization may be added, particularly if it is desired to make available in commerce a composition which is ready for polymerization and does not require further chemical additions in order to be used, as is commonly known in the art;

In order that this invention may be more readily underpreparation. a Certain of the Diels-Alder adducts of hexa generous halocyclopentadienes disclosed herein are new compositions of matter:

In the following; examples; in which parts are given by weight unless otherwise statemthe commonproperties;

of the resins were determined by the generally accepted procedures known in the art.

EXAMPLE 1- Fifty-two and eight-tenths parts of ethylene glycol and 90 parts of dieth'ylene glycol were charged into an est'erifioation or resin vessel manned-wan heatifigandYbreool ing means, an agitator, means for: maintaining an atmosphere of an inert gas over the reaction mixt'ure, means for removing water of esterifioation, temperature recording} means, charging inlets and outlets,. etc. The charge was blanketed with an inentatmosphereof nitrogen, agitated, heated to a temperature between about to 1'00: degrees centigrade, then 394.7 parts of 1,4,5,6;7,7-'hexachlorobi-- cyclo-(2.2.1 -5-heptene-2,3=dicarboxylic anliydi'ide (hereinafter referred to as HET), prepared by the method which involves the Diel's Alder reaction of hexachlorm cyclopentadiene with maleic anhydride, was blended into the agitated 'glycols. Seventy and eight-tenths parts of maleic anhydride was then blended into the charged reactants while thereaction mixture was being-raisedtoa temperature of about 16010: r70 degrees menugrade by application of external heat-.- The waterofi esterification liberated during the reaction wasseparated andperiodi' cally measured and the acid numbet of rthereactiont -mixr 6: EXAMPLE 4 Into a suitable reaction vesseljwere charged 105.41 parts otHET, 18 .5'part-sof maleic anhydride. 1613} pantsl'of sebacic -acid;- T617 parts ofii ethylene glycol and 2"8.6i parts of diethylene glycol. The esterifieation was carried out atanelevated temperature of, approximately, 14.8 degrees centignad'eunder an inertlaitmospliere; of carbon dioxide ration may also be'use'dwith equally good results, in

making the compositional ofil this invention.

I-ntoasuitable. reaction. vessel were chargedoll'lld parts of the adduct of hexachlorocyclopentadiene. and alpha all'yl glycerol ether, 31.0 parts of ethylene glycol; 73.1 parts of; adipic' acid and 147.1 partsfof malei-canhydride.

ture was also periodically measured to determine" the progress of the reaction. When an acid number ofyap:

proximately 55 was reached, 3.6 parts of tetrahydrofurfitrylalcohol added to the reaction mixture: Upon reaching anacid number of about 45, the entire contents of reaction. vessel. was cooled,. then. cast into pans Linden an: inert atmosphere. A. transparent, faintly colored, hard, brittle, soluble material, having 38,43percent by weight chlorine content, which melts in a temperature range above room temperature and below 100 degrees centigrade and has a specific at room temperature of about 1.45 was obtained.

EXAMPLE: 2*

0h hundred grams of the cast product recovered? in Example 1" was broken into small lumps, then added" in small portions, with agitation to grams of styrene maintained under an inert atmosphere, containing 0.03 gram of'hydroquinone, until completely dissolved. Complet'e solution consumeda eriod of more than 24' hours even with continued vigorous agitation. The resulting mixture was a clear, substantially colorless solution 'having' a viscosity of about 30 poises at 25 degrees centigrade on a" Gardner bubble viscometer;

EXAMPLE 3 diately selflextingu-ishing on removal froman oxidizing I The-data in the following example is reproduced from Example '15; ofour parent and copendingapplication, Serial Nov 308,91 .1 filed September 10,, 195 2,, new United States Patent 2,779,701 ,ofi whiclr'this application is a continuation-in-part.

cyclopent adiene and' 'maleic aniiydiide, half esterifietf witli methanol; adduct of liexallalocyclop'entadiene antlalpha The esterification. was. carriedoutuat. aneleuatefd tempera; ture: of. approximately 165 degrees centigrade under an inert atmosphere of carbon dioxide until an acidnumber of 3:0 was reached. To 1000" parts of the unsaturated po l'ymeriz'able resin was added 400 p'arfs of'sfyrene' con taining: 0. 11 part- .of hydroquinone inhibitor; Polymerizationwas oarriedout int-at manner after Example There. was obtained a: tough, clean. infusible, insoluble, resinous material, havinga-chlorine content. of: 30 percent andiwhich was sel f ext-inguishingupomremoval from oxidizing flame. I

The later examples set forth in chart form'illustrate formulations similar to.that of Example 4 except that polycarboxylic compounds other than sebacic acid are employed. These polycarboxylic compounds may be sel'ected from either aliphatic groups; shownin Qhart I or. aromatic groups: shown in Qhart II, and mayralsobe employed in varying proportions. All: Of-i the materials included inv these groups are characterized by the laclc of cross-linking, or copolymerizable"unsaturation in their.

structures. Such materials include: .isophthalic' acid}. succinic acid;. suberic acid; tetraclilorophthalic acid; di-

methyl succinic acid; seb'a'cic acid; adipic acid; '.azeflaic acid; and chlorinated'derivatives of the foregoing acids except tetrachlorophthalicac'id'; also; it is to be understood that the acid anhyd'rides are the equivalents: of the acids; Mixtures'o'f anyt-wo of tlie'acids-are contemplatedi The adduct of hexachlorocyclopentadiene and -rnal'eie acid. or 1,4,5,6,7,7-hexachlorobi'cyclo-(2L2;1 5-heptene 2',3-dicarboxylic acid (hereinafter referred to; as I-IET acid) or may be used interchangeably in: these exr amples,- It should also'be-understood that other adducts of hexahalcyclopentadiene maybe: used place ofi or I-IET acid. Among suchadducts which: may be used, in preparing the compositions of this rnventionare; adduct of hexahalocyclopentadiene and fumaric acid; adduct. of hexachlorocyclopentadiene and maleic anhydride di.-j esterified with allyl" alcohol; adduct of hexahalocycl pentadiene' and citraconi'c anhyd'ri'dfe; addfuct of hexah difiuorocyclopentadiene and ma leic anhyd'i 'ide'; adduerur hexahalocyclopentadiene and itaconic anhydride; adducti of hexaha locyelopentadienes and't-2rbutenelgt diol; and,

' 1 addu t of he a c y l nentadienezand chloro maleic ans hydride.

Chart 1 Pts. of Pts. of Pts. of Pts. Acid Percent Ex. Pts. of Pts. of Maleic Diethyl- Pts. of Pts. of Azelalc Pts. of Pts. 01' Iso- Num- Chlorine No. HEI Fumaric Anhyene Ethylene Adlpic Acid Dimer Diglycolic Sebaclc ber Base Acid Acid dride Glycol Glycol Acid Emory Acid Acid Acid Base Resin 901R 1 Resin Parts Percent Ultimate 'Ien- Tensile Elongation Styrene Chlorine Shore A, Barcol sile Strength, Strength in Break Self-extin- Ex. No. per 100 Resin Type Resin Hardness Hardness lbs/sq. in. Tested at 0.05 at Tensile, guishlng Resin Compound Tested at ln.lmln., Percent 2 in./m1n. lbs/sq. in.

30 19. 2 910 110 Yes. 30 19. 2 2, 180 65 Yes. 40 25. 8, 300 4. 0 Yes. 40 21 Yes. 40 26 do 9, 400 4. 0 Yes. 30 19 Flexible 2, 090 89 Yes.

1 Emory 901R is a mixture of Co and On dibasic acids, 85/15 ratio.

Chart 11 Char e of Char e Char e of Charge of Charge of Charge of Charge of Percent Parts Percent Self-Ex- EX. No. HE T of HE Fllmillc Ethylene Isoph- Phthallc Tereph- Chlorine Styrene Chlorine tlngulsh- Acid Anhy- Acid Glycol thallc Anhythalic Base P/H/R Resin mg dride Acid drlde Acid Resin Cpd 369. 5 76. 6 127. 9 35. 0 Yes. 3, 528 643. 3 1, 150 20 36 25 Yes. 352. 4 76. 6 127. 9 20 35. 0 25 Yes.

The following example is set forth to demonstrate the importance of the compositions of this invention in order to obtain a resin having high impact resistance qualifies. High impact resistance qualities are necessary for such applications as automobile bodies, structural walls, etc.

Example 15 The styrenated resin compositions of Example 2 and of Examples 6, 8, and 12 were compounded with 33 parts of finely divided calcium carbonate and 2 parts of Luperco ATC, a 50-50 mixture of benzoyl peroxide and tricresyl phosphate. These filled resins were used to make glass mat reinforced moldings in a matched metal die, steam heated press. The finished molded panels contained percent glass by weight and were 0.1 x 12 x 12 inches in size. These panels were fully cured by heating in the press at 120 degrees centigrade -for five minutes. They were then allowed to cool to room temperature, stored at 23 degrees centigrade for 24 hours and then subjected to an impact test at this temperature.

This impact test consists in dropping a steel ball having a diameter of 1.5 inches and weighing one half pound onto the molded panel which is firmly supported between two aligned horizontal rings, both six inches in diameter. The ball is dropped from a measured height onto the panelinto the center of the rings. A dye stain is then liberally applied to the side of the panel opposite the point of impact. When the excess stain is wiped from the panel, .any cracks caused by the impact become visible. -The ball is dropped at one inch intervals beginning at a vertical distance three inches above the panel. The point of failure is the lowest height in inches from which the ball is dropped causing a crack to be formed.

. The panels formed from the resins of Examples 2, 6, 8, and 12 and their points of failure are given below;

Panel from resin Point of failure In the claimed compounds of this application, which is a continuation-in-part of our previously filed application Serial Number 308,921, filed September 10, 1952, these polycarboxylic compounds free from cross-linkable, copolymerizable unsaturation are essential parts thereof and are used in order to improve the impact resistance and toughness of the final copolymerized resins.

The processing techniques and the chemical reactions depicted herein for producing the necessary ingredients to be used in making the compositions of this invention may also be varied without departing from our invention.

The temperature for carrying out the reaction between the polyhydric alcohols and polybasic acids ranges from degrees centigrade to 200 degrees centigrade, although higher or lower temperatures can be used; preferably around degrees centigrade to degrees centigrade is advantageously employed.

An inert gas such as nitrogen is passed through the mixture in a preferred procedure to accelerate the progress of the reaction and allow for good color of the product. The progress of the reaction is followed by measuring the rate of water liberated, by the viscosity of the resin, by its acid number, or by other methods commonly known in the art. The extent to which thereaction'is carried out will depend on a number of factors, such as the desired viscosity, melting point, duration or reaction, etc.

Esterification catalysts such as para-toluene sulphonic acid, benzene, sulphonic acid, beta naphthalene sulphonic acid, etc., or amines such as, pyridine, triethyl amine, quinoline, etc., may be added to the reaction mixture.

The proportion of polyhydric alcohol is approximately controlled by the total mol proportion of acids in the 9 esteri'ieationreaction miirturel In making certain compositions of our invention we prefer reac't the polyhydriealcohols and p'olybasi'c' acids in a roughly equi= molar proportion, however, either the acids or alcohol's maybe in substantial excess, if it is desired to'fornr alow 5 molecular weight polyester resiir. V

A chain stopper may bead ded in a minor pro ortion depending on the molecular weight of the-linear uiisaturated polyester chain" desired, in order" to rapidly terminate the' growth of the unsatt'lratjed polyester chain during; the esterific'ation reae'titm and when the desired acid number is being, approached; of, to rednee the lilifil" her of free ear-boxyl or hydroxyl groups, or te introduce ahydreiearb'en terminal residue: Among he eempeundfs which may be used as chain stoppers d 'gfthe' esteri f'cation reaction whereby the unsaturated p sj'ter chain produced are a wide variety of ibi ohydfie alcohols; snenas but'yl, hexyl, o'etyi; ded'ecyl; benzyl; and tetra nydrzefurfuryialcohols, or, menoeasie aeids s elt-as, acetic, prep'i'enie; b'utyrie, ethyl hexoie; and benjz'oici The solution or mixture of unsaturated} polyester and olefiiiie cross-linking agent is preferably made wane the unsaturated polyest'er isst'ill hot; as illustrated among the foregoin example thereby facilitating rapid sol-'u'tion'; Alternatively, the unsaturated polyester niay'peeeeled andstorett and when ready formiaing may he heated in order tofacilitate solution inthe" oi fiitieeross l trig agent which may als'eee-neatedi The-soliit-ioh may, tit-course, Be'made in the" cold; esp'e'eiallyif thereis any pessibilit of explosion in Handling the-het eiefinieeress linking agen or if polymerization of the olefi cross: Iihkin'g agent cannot be reve'nted wh at elevated-term peratures even by the preseneeef'inh ors therefor:

The proportion ofelefinie cro's's link g agent to unsaturated polyester may Beyar-ie'd within the iil'tim'ate of each without de artingnonithe:- scope of this invention; in order to the solht-i'o'n" or: mixture of tliisinventien whi nma be set t'cith'eififtis'ible', insolnii'l'e; polyester resin. For example; onlya small proportion of olelinic cross-linking agent is'- needed when the" pro= portion of reactive creseIinkabIe ol'efini'e Bendsiir the finsatu'ra'te'd polyester is very small: and a still smaller proportien of elefini-e erosseliiiking agent may Beene pio ed if itis desired to' reaet enl a parrot" the total 'dfsaidunsaturated bondsin' such olyester in the erase-- linkin weaetien; O'rithe other hand; amajor p'repee tienef olefini'e' ereselinliitig' agentte unsaturated oly ester may be employed when the prep'ortieti of reactive cress liiiitable olefinic bends in the unsaturatetlpolyester is high; and a still higher proportion ofolefinie cross-f linking a ent win' be required if it is" desired to react a major part of the totalof said uns'aturatetibends iiisuch' polyester in' the cross 'linkin'g reaction; In genera; the eoncentrationr ofthe unsaturated polyester the'lolfefiiiic cross-linking agent antiunsaturated polyester mixture may vary between about rosand 9opercent. ncerfa'in for: mulatiens' and in o'rdier' to" accentuates liege number-of tiesiraele properties in the polyester" resin produced, we find it preferable" to" mploy between about 'ang145 pe'iee'tit' of the olefinic' cross-linking agent by wei ht of thetotalresin andc'rossqinking-agent, e1g. styrene, when the unsaturated polyes'ter issimilar to that produced in Example" 1*. However, it is tobeunde'rtsjto'ctd tn tthi'sj pref rred c ncentration" is a varian'le wine is dictat liy the"part'icular roperties et' n materials" employed 5 and? the particular properties desired"- in "the" perye ter resin'produced) aelymerizatibn tensity of the order. of user to 1 percent or the nipositio'h may e add a to preventpremattne elymerizatien. Ame 'tne tb-ite'rs' wliierl may a'dvahtageously' be empieyetr tepr vent the prematurepolymerization of th mixture ofluh's'ati'irat'ed peiyester and" eiefinie "crossinking a ents it tire-iniat-ur" s toliestored or s p' n atter: to sun-a e are sith'stafices satires hydrdquihdne; T5

ire-es ate benzequinone, para=tertiary buty1 cat'echoL para' phenyl ene dia'miiie; trihi'trobenzene; and picric acid:

, Polymerization catalysts are preferably added to the mixtureof unsati'lratedpolyester and olefinic cross-linki'n-g' agent to effect setting or -curing.- Catalysts suchas Benzey1 peroxide, acetylperoxide, lauroyl peroxide; methyl ethyl ketone p'roxide, and cumene hydrop'eroxide; have been found satisfactory. Sucli' catalysts areu'sed -i'n apropo'rtionr of 0:01 to' 10 percent depen'ding'on the chi c'ienc'y of their action and whether or not substances which inhibit polymerization are present in the mixture to tbe' cross-linked. The polymerization reaction may" also be'hastened'by effecting itin the presenceof pr'o meters such as metals or metal salts; such as cobaltf'esinate; cobalt rna'leate, and cobalt naphthenate, or, By aminessuch as dibutyl amines; or mercaptans such as do'decyl merc'aptan-i These are used in proportions similar or smaller to that stated for catalysts.

The polymeri' zation' conditionsfor elfecting the cros's' li'nling reaction between the unsaturated polyesters of this iiivention" and the olefinic cross-linking agent rnay be selected from a wide variety of techniques but usually i'nvo'lv'ethe applieation ofheat or light. Although p'res sure is' not a required condition for effecting polymerization of the=polymerizable mixtures embraced within the invention; thereby providing for adecided advantage over other res'inmixtures known heretofore, it is sometimes advantageously employed, particularly when it is 66 sir-ed? tomakelaminates in preformed'shape. The pres sures found satisfactory for this purpose are relatively few compared to those required for molding or lami n'at'ing other type-resins than involved hereinand maybe of the order of that obtained by pressing glass plates having a-fiher :glas's mat or laminate impregnated with the polyester resin sandwiched therebetween. The temperature at" which polymerization iseffected depends onavariety of factors; particularly the boiling point of the olefinic cross-linking agent and the exo tnermie characteristics of the polymerization mixture.- A temperature is selected which will give a suitable re-- action rate and yet not cause substantial volatilization, and inthe case of producing very thick castings, which will not produce a product which is crazed, cracked, etc.

Various hexahalocyclopentadienes may be employed in inaking compositions embraced within the scope of this invention; As used herein and inthe appended claims the term halo includes the chloro, bromo and fluoro substituted cyclopentadienes wherein all of the hydrogens are replaced by one or more of the foregoing halogens-t While hexaehlorocyclopentadiene is today the most readilyavailable' commercial hexahalocyclopentadiene, wehave found that the mixed perhalo compounds are useful in making Diels A lder adducts which can be chemically combined into the saturated polyester components of this invention.

Intact; hexachlorocyclopentadiene' in which one or two of the chlorine atoms has been replaced with bromine, appears to aiford an even higher degree of flame retardanee in the polyester resins. The polyester resins made from a hexahalocyc'lopentadiene in which some of the chlorine of heXachlorocyclopentadiene has been re placed with fluorine atoms, are exceedingly interesting materials possessing enhanced heat resistance and aging properties. "The foregoing applies whether the hexahalo cyclopentadiene is utilized as a raw material in the mak ing" of the copolyinerizable linear polyester or the unsaturated cross-linking agent.

' Thecompounds useful in'rnaking adducts of hexahalocyclopentadienes are dienophiles having a plurality of esterifiable groups; said dienophiles being defined as acti va'ted olefinic" (or aeetylenic) compounds whichWill'fbrfii a Diels-Alder addition adduct' with a conjugated dien'e system=.- These functional groups eap'able of ester ificietionand having utility hereinare' found'in 'com'po' t'md's 11' such as substituted or unsubstituted acids, anhydrides, acid halides, alcohols and esters, as hereinbefore illustrated.

The hexahalocyclopentadiene radical may be combined into the polycarboxylic acid unit of the unsaturated polyester chain in a variety of ways such as by efliecting the Diels-Alder reaction of the hexahalocyclopentadiene with unsaturated polycarboxylic acids such as maleic or fumaric; substituted maleics or fumarics such as, citraconic, chloromaleic, mesaconic, and pyrocinchonic; acetylene dicarboxylic acids; and also ethylenic substituted succinic anhydrides or acids, such as aconitic and itaconic, and endomethylene tetrahydrophthalic acid or anhydride, etc. Instead of employing the polycarboxylic acids or anhydrides in the Diels-Alder reaction, adducts of hexahalocyclopentadiene with substances which produce an equivalent polyester chain upon reaction with a polyhydric alcohol can be used; for instance, acid chlorides, or, esters of the acids or anhydrides may also be used. A typical illustration is had in the Diels-Adler reaction of hexachlorocyclopentadiene with fumaryl chloride to produce l,4,5,6,7,7 hexachlorobicyclo (2.2.1) heptene- 2,3-dicarbonyl chloride followed by the esteriflcation of this with ethylene glycol and maleic anhydride to produce the unsaturated polyester. In place of the acid chloride, diesters such as dimethyl maleate may be employed.

Alternatively the hexahalocyclopentadiene radical may be combined into the polyhydric alcohol unit of the unsaturated polyester chain in a variety of ways such as, by effecting the Diets-Alder reaction of the hexahalocyclopentadiene with unsaturated polyhydric alcohols such as, butene-diol or pentene-diol. Other suitable compounds are ethers or esters derived from polyhydric a1cohols having at least three hydroxyl groups, one of which is esterified or etherified with an unsaturated alcohol or acid reactive with hexahalocyclopentadiene in the diene synthesis. For instance, allyl or vinyl glycerol ethers, allyl or vinyl pentaerythritol ether; and unsaturated acid esters of glycerol or pentaerythritol, such as acrylic or methacrylic esters thereof may be used. Instead of employing a polyhydric alcohol in the Diels-Alder reaction, adducts of hexahalocyclopentadiene with substances which produce an equivalent unsaturated polyester chain, upon reaction with a polycarboxylic acid can be used; for instance, esters of the alcohols may also be used.

The unsaturated polyester chains produced by effecting the Diels-Alder reaction of hexahalocyclopentadiene with an unsaturated polycarboxylic acid or polyhydric alcohol, followed by the esterification of the product so produced with a polyfunctional alcohol or acid, can be rendered copolymerizable by chemically combining in such polyester chains, a reactive and unsaturated chemical ingredient which retains its active unsaturation after its chemical combination into the polyester chain. Among the materials which may gainfully be employed for this purpose are the unsaturated polycarboxylic acids such as, maleic, fumaric, citraconic, itaconic, and acetylene dicarboxylic acids and esters and halogen substituted derivatives thereof, etc.; the unsaturated polyhydric alcohols such as butene-diol, dipropylene glycol and pentenediol, also unsaturated hydroxy ethers such as allyl or vinyl glycerol ethers and allyl or vinyl pentaerythritol ethers, etc.; still other chemical compounds comprising an ethylenic or an acetylenic linkage which are not rendered unreactive in the polyester chain by'their chemical combination into the polyester chain by way of other functional groups, whereby the mixed esters of adducts of hexahalocyclopentadiene are produced.

Another method of providing for copolymerizable unsaturation in the polyester chain which may be employed involves effecting the diene synthesis of a hexahalocyclopentadiene with a polyoasic alcohol or acid or ester, or equivalents thereof, which contains at least two olefinic linkages, one of which is reactive'in the diene synthesis, While the others which are unreacted are capable of being copolymerizable in the cross-linking reaction. Among the materials which are useful for this purpose are acetylenic compounds and di-olefinic and poly-olefinic compounds.

Alternatively, or in addition to including the flame retardant component in the unsaturated polyester, we have found that the chlorine content of the final polyester formulations may be obtained, or, substantially increased, by employing a cross-linking agent which also contains the component which imparts flame retardance to the final compositions of this invention. Among such cross-linking agents which may be useful for this purpose are the following: Diallyl-1,4,5,6,7,7-hexachlorobicyclo-(2.2.l)-5- heptene-2,3-dicarboxylate; diallyl-1,4,5,6,7,7-hexachloro- 2 methylbicyclo (2.2.1) 5 heptene 2,3 dicarboxylate; diallyl-1,2,4,5,6,7,7-heptachlorobicyclo-(2.2.1 )-5- heptene-2,3-dicarboxylate; and triallyl-1,4,5,6,7,7-hexachlorobicyclo (2.2.1) 5 heptene 2 acetate 2,3- dicarboxylate. These compounds can be prepared by reacting-hexachlorocyclopentadiene with the indicated dicarboxylic acid and esterifying the resultant product with an unsaturated alcohol such as allyl alcohol. Other cross linking agents may advantageously be employed; for example, reaction products of hexachlorocylcopentadiene with isoprene or butadiene retaining a reactive unsaturated linkage can be used as cross-linking agents directly without further reaction. Still other methods for the preparation of the unsaturated cross-linking agents, employing type reactions known to the art, will be apparent from the foregoing. In addition, materials such as triallyl cyanurate may be employed for improving heat resistance; diallyl maleate and similar monoor poly-vinyl or monoor poly-allyl derivatives, divinyl benzene, monochlorostyrene, and diallyl phthalate are also useful.

It is apparent from a consideration of the foregoing examples and the foregoing discussion that the particular chemical ingredients selected and their relative proportions may be varied over a wide range to produce a wide variety of compositions embraced within this invention. It should be emphasized that modifications can be made to accentuate any given property or combination of properties desired. For example, hardness in the final polyester resin can be varied by using short chain polyhydn'c alcohol and acids or long chain polyhydric alcohols and acids; the viscosity of the mixture comprising the unsaturated polyester and the olefinic cross-linking agent may be varied by changing the ratio of unsaturated polyester to olefinic cross-linking agent; and the curing characteristics of such mixtures can be varied by changing the kind and proportion of polymerization catalyst employed. In order to accentuate both flame retardance and heat resistance, we prefer that the hexahalocyclopentadiene content should not be less than that suflicient to supply a final product of not less than ten percent of halogen by weight of the polyester resin compositions; the upper limit for the hexahalocyclopentadiene content is generally dictated by practical limits determined by the minimum necessary concentration of glycols and unsaturated dibasic acids not being adducts of hexahalocyclopentadiene and olefinic compounds to give resinous compounds capable of being hardened and this upper limit is about 60 percent. Flame retardance may be accentuated by adding to the unsaturated polyester containing a hexahalocyclopentadiene component, a cross-linking agent which also contains flame retardant properties obtained from a hexahalocyclopentadiene in chemical combination therewith. It may be further accentuated by esterifying a polycarboxylic acid and polyhydric alcohol which each contain the hexahalocyclopentadiene flame retardant component of this invention and cross-linking this with a fire resistant cross-linking agent. Mechanical strength can be accentuated, for example, by employing diallyl diglycol carbonate as the cross-linking agent with a linear unsaturated polyester resin of this invention, similar to that given in Example 20, and forming glass cloth lami- 13 nates one-eighth inch in thickness. The flexural strength at room temperature of such a laminated resin is as high at 85,000 pounds per square inch and modulus of elasticity is 4.16 pounds per square inch.

The properties of the compositions of this invention can be varied substantially by incorporating modifying agents before, during or after any of the processing steps employed. For example, instead of producing articles of commerce from the compositions of this invention which are in the form of castings or laminates as previously described herein, a foamed type article may be made by incorporating a small percentage of a foaming agent such as sodium bicarbonate into the solution of unsaturated polyester dissolved in cross-linking agent and thereafter efiecting the copolymerization in the presence of catalysts and heat to produce the foamed article. mulations which are useful for making moldings embodying the compositions of this invention may be made by mixing into the unsaturated linear polyester and olefinic cross-linking agent mixture a fibrous reinforcing medium and/ or an inert filler such as chopped fiber glass rovings, macerated fabric, asbestos fibers and mica, which serve as fiibrous reinforcing media and incorporating a small percentage of a mold lubricant, catalyst and/or promoter.

An infinite variety of products may also be prepared, which embody the copolymers of this invention, by copolymerizing the linear unsaturated polyester materials produced in accordance with this invention, as in Example 1, with a mono-olefinic cross-linking agent in the presence of another copolymerizable linear polyester material having different structure than that produced by this invention. For example, by dissolving 23.1 parts of the product of Example 1 and 4.3 parts of an unchlorinated commercial polyester resin dissolved in styrene and especially designed for imparting flexibility and designated as Paraflex P-13 (made by Rohm & Haas Company, Philadelphia, Pennsylvania) and 2.3 parts by weight of styrene and effecting the copolymerization of the mixture by a catalyst, a material is produced which has better flexibility and different properties than any materials produced heretofore. It is to be understood that dyes, pigments, plasticizers, lubricants and various other modifying agents are contemplated as being incorporated in certain formulations to produce'compositions embraced in this invention in order to obtain or accentuate any given property.

We claim:

1. A polymerizable mixture comprising (A) a copolymerizable linear polyester comprised of (1) a polyhydric alcohol, (2) an adduct of hexahalocyclopentadiene and a polyhydric alcohol containing aliphatic carbon-to-car- Forbon unsaturation wherein the halogen is selected from the group consisting of chlorine, bromine, fluorine and mixtures thereof, (3) a polycarboxylic compound selected from the group consisting of polycarboxylic acids, acid anhydrides, acid halides and acid esters containing aliphatic carbon-to-carbon unsaturation, (4) a polycarboxylic compound selected from the group consisting of (a) saturated aliphatic polycarboxylic acids and saturated aliphatic polycarboxylic acid anhydrides; and (b) aromatic polycarboxylic acids and aromatic polycarboxylic acid anhydrides; and (B) a polymerizable monomer containing a CH '=C= group.

2. A mixture of claim 1 wherein the hexaha'locyc-lopentadiene of the adduct (2) is hexachlorocyclopentadiene.

3. A mixture of claim 1 wherein the polymerizable monomer (B) is styrene. v

4. A mixture of claim 1 having a polymerization in hibitor added thereto.

5. A mixture of claim 1 when polymerized to an infusible, insoluble, resinous composition.

6. A mixture of claim 1 when mixed with an inert filler and polymerized to an infusible, insoluble, resinous composition.

7. A reinforced plastic article comprising a mixture of claim 1 when polymerized to an infusible, insoluble, resinous composition, and a fibrous reinforcing medium.

8. A laminated article comprising a plurality of sheets of glass fibrous material and as a binder therefor, an insoluble, infusible, resinous composition resulting from the polymerization of a composition defined in claim 1.

9. A composition of matter comprising a copolymerizable linear polyester comprising (1) a polyhydric alcohol, (2) an adduct of hexahalocyclopentadiene and a polyhydric alcohol containing aliphatic carbon-to-carbon unsaturation, wherein the halogen is selected from the group consisting of chlorine, bromine, fluorine and mixtures thereof, (3) a polycarboxylic compound selected from the group consisting of polycarboxylic acids, acid anhydrides, acid halides and acid esters containing aliphatic carbon-to-carbon unsaturation, and (4) a polycarboxylic compound selected from the group consisting of (a) saturated aliphatic polycarboxylic acids and saturated aliphatic polycarboxylic acid anhydrides; and (b) aromatic polycarboxylic acids and aromatic polycarboxylic acid anhydrides.

10. A composition of claim 9 wherein the hexahalocyclpentadiene of the adduct (2) is hexachlorocyclopentadiene.

No references cited.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,898,256 I August 1959 Paul Robitschek et a1.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, lines 26 and 27, for "artricles" read articles column 3, lines 13 to 16, and lines 21 to 24, the extreme lefthand portions of Equations I and II, each occurrence, the formulas should appear as shown below instead, of as in the patent:

c1 c1 column 4, line 65, for "catlyst" read catalyst column 5, line 47, for "On" read One column 6, line 61, for "hexae halcyclopentadiene" read hexahalocyclopentadiene column 8, line 71, after "benzene" strike out the comma; column 13, line 23, for "fiibrous" read fibrous Signed and sealed this 19th day of July 1960 (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

1. A POLYMERIZABLE MIXTURE COMPRISING (A) A COPOLYMERIZABLE LINEAR POLYESTER COMPRISED OF (1) A POLYHYDRIC ALCOHOL, (2) AN ADDUCT OF HEXAHALOCYCLOPENTADIENE AND A POLYHYDRIC ALCOHOL CONTAINING ALIPHATIC CARBON-TO-CARBON UNSATURATION WHEREIN THE HALOGEN IS SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE, FLUORINE AND MIXTURES THEREOF, (3) A POLYCARBOXYLIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF POLYCARBOXYLIC ACIDS, ACID ANHYDRIDES; ACID HALIDES AND ACID ESTERS CONTAINING ALIPHATIC CARBON-TO-CARBON UNSATURATION, (4) A POLYCARBOXYLIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF (A) SATURATED ALIPHATIC POLYCARBOXYLIC ACIDS AND SATURATED ALIPHATIC POLYCARBOXYLIC ACID ANHYDRIDES; AND (B) AROMATIC POLYCARBOXYLIC ACIDS AND AROMATIC POLYCARBOXYLIC ACID ANHYDRIDES; AND (B) A POLYMERIZABLE MONOMER CONTAINING A CH2=C=GROUP.
 8. A LAMINATED ARTICLE COMPRISING A PLURALITY OF SHEETS OF GLASS FIBROUS MATERIAL AN AS A BINDER THEREFOR, AN INSOLUBLE, INFUSIBLE, RESINOUS COMPOSITION RESULTING FROM THE POLYMERIZATION OF A COMPOSITION DEFINED IN CLAIM
 1. 